Internal-combustion engine variable combustion chamber



Nov. 6, 1951 F. D. BUTLER 2,573,688

INTERNAL-COMBUSTION ENGINE VARIABLE COMBUSTION CHAMBER Filed Nov. 26, 1947 4 Sheets-Sheet 1 VENTOR.

NOV. 6, 195] BUTLER 2,573,688

INTERNAL-COMBUSTION ENGINE VARIABLE COMBUSTION CHAMBER Filed Nov. 26, 194'? 4 Sheets-Sheet 2 III Nov. 6, 1951 B R 2,573,688

INTERNAL-COMBUSTION ENGINE VARIABLE COMBUSTION CHAMBER Filed Nov. 26. 194': 4 Sheets-Sheet a 42 4s 28 44 26 45 a4 2s A 46 2.

d 50 3a in Nov. 6, 1951 Filed NOV. 26, 1947 Amount Size gas combustion charge chamber cubical cubical inches. inches.

F. D. BUTLER WITH VARIABLE COMBUSTION CHAMBER Compression ratio.

Expanratio.

Amount gascharge cubical inches.

Size

combustion chamber cubical inches.

INTERNAL-COMBUSTION ENGINE VARIABLE COMBUSTION CHAMBER Compres- Bion ratio.

4 Sheets-Sheet 4 WITHOUT VARIABLE COMBUSTION CHAMBER Expansion ratio.

JMQZZ/lf 1 Patented Nay 1951 UNITED STATES PATENT OFFICE" INTERNAL-COMBUSTION ENGINE VARI- ABLE COMBUSTION CHAMBER Frank David Butler, United States Navy Application November 26, 1947, Serial No. 788,304

8 Claims. (c1. 123-18) (Granted under the act oi" March 3,1883, as"

amended April so, 1928'; 370 0. G. 157) piston means for automatically accomplishing the changes in said variable cubical size of such combustion chamber, and a, means of automate ically controlling such yielding of said main piston means, all-primarily for the purpose of conserving fuel.

In combination with the engine combustion chamber, main piston, crank-shaft, connecting rod, and the forced feed lubrication oiling system of said crank-shaft and connecting rod, further objects of this invention include the provision of the following; an auxiliary cylinder trunnion journal supported within said main piston and having a closed end away from said crankshaft and a removable head end towards said crank-shaft; a cylindrical auxiliary piston secured to the end said connecting rod away from said crank-shaft and being reciprocatably slidable within said auxiliary cylinder and having a tubular end extending towards said crank-- shaft; a splined key portion forming a part'of a cylindrical portion of said connecting rod and located midway between said auxiliary piston and said crank-shaft; a removable head for said auxiliary cylinder and constructed to receive said cylindrical splined key portion of said connecting'rod in a slidable manner; a closed cylindrical chamber formed between other thantubular end said auxiliary piston and said closed end said auxiliary cylinder; access means extending from said forced feed lubrication oiling system of said crank-shaft through said connecting rod to said closed cylindrical chamber; a relatively small orifice restriction in said access; a check valve in said access and seating towards said crankshaft; 9. closed annular shaped chamber formed between said tu ular end said auxiliary piston and the remov 1 head of said auxiliary cylinder; a plurality of port connections extending between said annular shaped chamber and said access ahead of said orifice and said check valve; a series of holes extending longitudinally through said auxiliary piston from said closed cylindrical chamber side to said tubular side thereof; an annular shaped pressure relief valve seating against said series of holes in said auxiliary pistontowards said closed cylindrical chamber; an elongated resilient spring movable with said auxiliary piston and exerting pressure against said relief valve to retain it in contact with its seat; a relatively small orifice leading from said closed cylindricaI chamber to the atmosphere for venting purposes; a spring loaded pressure relief valve seating over such vent orifice towards said closed cylindrical chamber; a dash-pot for cushioning purposes and formed between a projection of said auxiliary piston and a recess in said closed end said auxiliary cylinder; a dash-pot likewise for cushioning purposes and formed between a projection at tubular end said auxiliary piston and a recess in said removable head said auxiliary cylinder; and, means for automatically reciprocatably sliding said auxiliary cylinder (mounted within said main piston) over said auxiliary piston by and through said lubricating oil under hydraulic pressure acting in conjunction with changes in pressures within said combustion chamber and thus automatically regulating hydraulically the cubical size of said combustion chamber.

With the provision and application of the foregoing to the modern automobile or other internal combustion engine, the object is to produce thereby an engine comparable in eificiency to the diesel engine, and in which th main pistons thereof are made full floating hydraulically in producing such engine. Thus with the foregoing in view the various other novel features and advantages of this invention will become apparent from a reading of th following specification and the accompanying drawings of which latter:

Fig. 1 is a transverse section of the assembled invention device as applied to one of the six cylinder units (number two unit looking to the rear) of a modern automobile engin and as it would appear taken on the dotted and broken line li of Fig. 2; Fig. 2 is a longitudinal section of my invention device assembly as it would appear on the dotted and broken line 2-2 of Fig. 1; Fig. 3 illustrates a slight variation in the assembly of my invention device in transverse section and partly in side elevation and as it would appear on the dotted and broken line 3-3 of Fig. 4; Fig. 4 is a longitudinal section of the device as it would appear taken on the dotted and broken line 4-4 of Fig. 3; Fig. 5 is an enlarged detail section of the air venting relief valve illustrated in smaller scale in Figs. 1 to 4 inclusive;

- and, Fig. 6 is in the format a chart illustratin variable combustion chamber.

With further reference to the drawings, similar numerals indicate similar parts in the several views:

The numeral I indicates the usual en bloc cylinder casting, 2 the en bloc cylinder head casting, 3 the head gasket, 4 the head holding down bolts, 5 the fuel inlet valves, 6 the exhaust valves, I one of the valve operating rods, 8 the combustion chambers, 9 one of the spark plugs, II) the water jacket, II the main pistons. I2 one of the connecting rods, and I3 the crank-shaft, all of which are normal to such automobile engine.

In combination with the foregoing I provide a variation in the crank-shaft I3 and connecting rod I2 as follows; a relatively small annular shaped groove I4 is machined in the crank and/ or connecting rod journal l5 of the crank-shaft I3 so that lubricating oil'under pressure can be continuously supplied from the usual diagonally extending (lubrication oil supp y) hole IS (in I3) to the radially extending hole II (in insert bearing I8) and therethrough into the elongated access hole I9 in connecting rod I2; the upper portion of the connecting rod I2 is constructed round in heu of the usual H shape and is threaded and shouldered at its extreme upward end to receive thereover the auxiliary piston 20 and has said access hole I!) extending practically throughout its entire length, said hole terminating at its extreme upward end in a restriction orifice 2| which latter in turn terminates at its upward end in a spring loaded check valve 22 seating towards said crankshaft and thus allowing oil under pressure to pass upwards therepast into the cylindrical chamber 23 (above 28) but not downwards therepast into orifice 2I; one or more radially extending ports 24 (in I2) connect the access hole I9 with the upper end of the annular shaped chamber 28 within and below piston 20 and allow oil under pressure to pass freely thereinto or therefrom said chamber 25; and, the rod I2 .is shouldered at 28, and is provided with a splined type of key 21 (located-in about its mid-length) for the purpose of maintaining alignment between the connecting rod and main piston journals and which (along with 26) will be described more in detail hereinafter.

The variation in the usual main piston II consists of providing practically the entire combustion chamber cubical size controlling device therein and includes the provision of the following therewithin; a T shaped auxiliary cylinder 28 having one end thereof closed and having also a cylindrical bore 28 concentric therewith and adapted to receive (in a slidable and reciprocatable manner) the auxiliary piston 2|) and constructed so as to be supported on the trunnion .journals 30 in the usual bore 3| of the main piston II; these trunnion journals 3!) being constructed H shaped and adapted to be secured tightly over journals so should be manufactured of steel and heat treated and ground (similar to the usual piston pins which they substitute for); for purposes of assembly and removal of piston 20 in bore 28 (in 28) a flanged bonnet or head 34 is headed machine screws 35 and (for joint seal purposes) a copper gasket 36 is inserted between the machined surfaces 28 and 84; for purposes of maintaining alignment of connecting rod journal I! and the journals 30. a splined type keyway 31 (preferably like illustrated in Fig. 3) is machined in the lower end of head 34 and operates in conjunction with the splined key 21 (of rod I2 and previously mentioned) in maintaining such alignment; a plurality of diagonally extending holes 38 (in piston II) furnish access for lubricating oil supply from beneath the usual main piston II oil rings 38 to the Journals 30 in bore 3|; both the auxiliary cylinder 28 and the auxiliary piston 24 should (for long endurance purposes) be manufactured of steel and heat treated and the bore 29 and outside surface of 28 ground to a minute clearance therebetween, the latter being allowable inasmuch as parts are submerged in oil and that very little heat is present at this location; for purposes of preventing minute quantity of oil leakage along the outer surface of 28', the latter is machined with a series of baille grooves 48 and/or the piston 28 may be equipped with (as illustrated in Figs. 3 and 4) a leather or neoprene packing ring 4I and/or a plurality of snap type piston rings 42 and/or all three, however only 40 are considered a necessary or desirable; for purposes of fluid release and fluid pressure relief from cylindrical chamber 23 (above 20) to annular chamber 25 (in and below 20) a series of access holes 43 are drilled in and extend through auxiliary piston 20 from chamber 23 to chamber 25; an annular shaped fluid release or relief valve 44 covers and is seated against the lower end edges of hole 43 and is retained in contact with such seat by the elongated resilient spring 48 which latter bears upwards against said valve 44 and downward against the flanged collar 46 which latter is slidable over rod I2 and is seated downward against the shoulder 26 (previously mentioned) of rod I2; piston 20 is tubular shaped on its under side and encloses spring 45 and valve 44 and also forms the annular shaped chamber 25 therebetween it, the rod I2 and the head 34; the upper end of cylinder 28 is closed and the'cylindrical chamber 231s formed therebetween it and the upper end of piston 2|); a restriction orifice 41 covered with a spring loaded pressure relief valve 48 is located in the top of cylinder 28 and furnishes an air vent relief between the top of chamber 23 and atmospheric pressure within piston I I; a dash-pot 49 (Fig. 1) is formed between a shoulder on the upper end of 20 and a recess shoulder in the upper end of 28, and which dash-pot cushions the cylinder 28 as it approaches the downward end of its travel; a similar dash-pot 59 (Fig. 1) i formed between the lower side of collar 4'3 and a recess in the head 34, and which dash-pot 58 cushions the cylinder 28 as it approaches the upward end of its travel over piston 20; and, a copper gasket 5| is inserted between the upper end of I2 and the flanged portion at upper end of 20 for making a tight joint at this location.

Assuming that the cylinders 28 are all at their full downward travel over auxiliary pistons 28 and that the engine is started (in the usual manner of starting an automobile engine) and is operated slowly a few moments while warming up. Almost instantly pressure would build up on the lubricating oil system thereof and the pressure gage thereof should normally register 40 pounds gage. Oil under pressure (mixed at first with a small quantity of air) would then be supplied to access holes i8 in rods l2 and would fill chambers 25 immediately and (during that portion of the engine cycle of operation of exhaust, suction and the first half of the compression strokes of all the main pistons ll) oil under pressure from l8 would also enter chambers 23 via orifices 2| and past check valves 22. Thus, due to the fact that the projected area of the upper end of 28 is greater than the lower end thereof because of projected area of rod l2 below 28, the oil under up to seven and as it started to exceed this amount, due to the combustion pressures in combustion chambers 8 resulting from this compression ratio and to the resulting pressures in chambers 23 and also to the settings of valves 44 and 48, the valves 44 and 48 would all be lifted from their seats. This lifting of valves mentioned would cause any air in chambers 23 to be ejected through valves 48 to atmospheric pressure within the pistons H, and if no air were present in said chambers 23 then a minute quantity of lubricating oil would be ejected via said valves 48. Simultaneously lubricating oil would be ejected from all chambers 23 to 25 via valves 44, and, as the chambers 25 are all smaller than chambers 23 due to presence of cylindrical portions of rods l2 therein, a small quantity of lubricating oil would be ejected from each of'the chambers 25 back into the engine lubrication system via access ports 24 and holes IS in rods I2. As conditions of engine operation would seldom be such as to cause full length down travel of cylinders 28 instantly, and likely never would happen, the usual relief valve on the lubricating oil system, plus oil leakage around bearings and oil ejected out through valves 48, would prevent any injury to said lubricating oil system due to such a surge in oil pressure therein. Under normal conditions the usual engine lubricating pump would handle the additional load of this device, however in the event the engine bearings become loose a larger pump than normal would be recommended. As illustrated in this particular case (Figs. 1 to 4 inclusive) the existing relations of the projected area of auxiliary piston 28 to main piston II is 4 to 1, thus a movement of 1 cubical inch of oil from or to chamber 23 will result in 4 cubical inches in change in size of combustion chamber 8, also the pressure on the oil in 23 (and/or vacuum) would likewise be 4 times whatever it happened to be in chamber 8. Thus as the mean pressure throughout the four stroke cycle is relatively low, especially under reduced power conditions of engine operation, the tendency is for the auxiliary cylinders 28 to continually work upward, especially during-the exhaust, suction and first half of the compression strokes of the main pistons II. This normal up travel of cylinders 28 combined with the down travel thereof cause the release of oil fluid from chambers 23 by valves 44 and 48 (whenever pressure in 23 exceeds 4 times combustion pressure in 8 caused by compression ratio therein of '7, in case illustrated) results in a constant compression ratio of 7 (depending upon setting of valves 44 and 48) being hydraulically and automatically maintained;

The object being to maintain as high a compression ratio as possible (depending upon the fuel used) without the dangers of predetonation of the fuel mixture.

During periods of steady operation of the engine there would be practically no movement of the cylinders 28 inrelation to the auxiliary pistons 28 due to the fact that the setting .of valves 48 are a trifle below the settings of valves 44 and that the oil entering chambers 28 at a relatively low pressure through orifices 2| (during certain strokes of the pistons ll) approximately equals the oil ejected from chambers 23 via the smaller orifices 41 (but at an extremely higher pressure) during the peak of the combustion periods. Due to the fact that valves 44 and 48 seat instantly whenever (after lifting) the relative pressure in combustion chambers 8 falls below their settings, and due to the oil being trapped in the dash-pots 48 (described hereinafter) the chambers 28 should never be void of oil. Any rapid movement of the cylinders 28, as they approach the ends of their full travel over pistons 28, is prevented by oil trapped in the dash-pots 48 and 50 seeping out slowly thererom.

By and through this type of automatic and hydraulic regulation of the cubical size of the combustion chamber 8 (of each of the engine cylinder units) extremely high thermal efliciency of the engine under reduced power operation can be produced withoutefiecting the volumetric efficiency of the engine under full power conditions of operation. Thus under medium power operation the thermal eflioiency of this type of engine should approach that of the diesel type engine under similar conditions.

With reference to comparison tables illustrated in Fig. 6, the results of using a variable combustion chamber can be more clearly understood and when it is realized that a slight increase in compression ratio results in a major increase in combustion pressure no further description of these tables is considered necessary.

The invention herein described and hereinafter claimed may be manufactured, used and sold by or for the Government of the United States of America for governmental or other purposes without the payment of any royalty thereon or therefor.

I claim:

1. In an internal combustion engine of the reciprocating type having a force feed lubrication system, in combination with an engine cylinder having a compression chamber' and a piston, an auxiliary compression controlling unit comprising an auxiliary cylinder within said piston and having wrist pins extending into the walls thereof, a connecting rod terminating in an auxiliary piston within said auxiliary cylinder and having an internal passageway connected to the source of the force fed lubricant, means establishing communication between said passageway and the working chamber formed within said auxiliary cylinder, and said auxiliary unit having a restricted orifice for release of lubricant from said working chamber.

2. In an internal combustion engine of the reciprocating type having a force feed lubrication system, in combination with an engine cylinder having a compression chamber and a piston, an auxiliary compression controlling unit comprising an auxiliary cylinder within said piston and having wrist pins extending into the walls thereof, a connecting rod terminating in an auxiliary piston within said auxiliary cylinder and having an internal passageway connected to the source of the force ted lubricant, means establishing communication between said passageway and the working chamber formed within said auxiliary cylinder, and a relief valve opening from said working chamber into the interior oi the engine piston.

3. In combination with a cylinder of an internalcombustion engine, an engine piston forming with said cylinder ammpression chamber, said piston carrying means providing an auxiliary cylinder bore therewithin, a connecting rod carrying an auxiliary piston that is disposed intermediate the ends of said bore, a sleeve around said rod and closing the adiaccnt end 0! said bore so that the auxiliary cylinder is divided into two chambers by the auxiliary piston, said connecting rod having an internal passageway for conveying fluid under pressure to the interior of said'auxiliary piston, and the latter having ports establishing communication between said passageway and said two chambers.

4..In the combination 0! claim 3. a compression spring-arranged'between said sleeve and one end or said auxiliary piston and an annular disc valve urged against said end by said spring.

5. In the combination defined in claim 3, a checkvalve in oneot said auxiliary piston ports,

opening from said passageway into one of said chambers, and a second check valve controlling communication between said chambers.

6. In combination with a cylinder'oi an internal combustion engine having a lubricant reser-.

voir an engine piston forming with said-cylinder" a compression chamber, a separate auxiliary .cyl-

ing clearance space within the engine piston open to the lubricant reservoir, a hollow connecting rod open to receive lubricant and designed'to discharge same into the upper chamber by way of said auxiliary piston, a check valve in said auxiliary piston to control said discharge, a relief valve in the upper end of said auxiliary cylinder to release lubricant into said upper chamber, said auxiliary piston having a restricted oriiice interconnecting said end chambers, and said rod having a port interconnecting its hollow interior with the lower chamber of said auxiliary cylinder.

7. In the combination defined in claim 6, a spring-pressed valve in said lower chamber for resisting intercommunication between said chambers by way of said restricted orifice.

8. In the combination defined in claim 6. means at both ends of said auxiliary piston in association with complemental means at both ends of said auxiliary cylinder, said means designed'to serve as dash pots.

FRANK DAVID BUTLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number. 1 Name Date 752,936. Vogt Feb. 23, 1904 1,013,619 Sauvan Jan. 2, 1912 1,252,269" Johnson et al Jan. 1, 1918 1,506,540 Matson Aug. 26, 1924 1,610,137 Kratsch Dec. 7, 1926 1,637,245 Scully July 26, 1927 1,825,163 Schweter Sept. 29, 1931 2,134,995 Anderson Nov. 1, 1938 2,252,153 Anthony Aug. 12, 1941 2,372,472 Campbell 'Mar. 27. 1945 2,380,907 Hall July 31, 1945 2,406,511 Roth Aug. 27, 1946 

